The present invention relates to a communication network that includes several nodes, which are equipped with transmitter/receiver units for wireless communication; at least a few of these nodes—referred to as mobile nodes—are installed on mobile machines. The present invention also relates to an operating method for a communication network of this type.
A communication network of this type that is used in the field of agriculture is made known, e.g., in DE 43 22 293 A1.
Wireless communication networks are known in general, in a wide variety of types. Even though a large portion of the populated surface of the earth is covered by cellular mobile communication networks, there are gaps in this coverage, particularly in agricultural areas, and it cannot be assumed that this problem will be fundamentally resolved. Rather, it is expected that the total surface area covered by modern, broadband, fourth-generation, mobile communication networks, e.g., UMTS networks, will remain smaller than that covered by the established, third-generation networks based, e.g., on the GMS standard. A communication network designed to function anywhere on the surface of the earth must therefore be designed to not rely on the availability of the cellular mobile communication infrastructure, either at all, or at least not continuously.
Another known type of communication network for wireless communication are WLANs (Wireless Local Area Networks) or WIMAX networks, which usually operate based on a standard in the IEEE 802.11 or 802.16 family. The range of radio contact in a network of this type is typically 30 to 100 m, and, at best, up to 300 m in the case of a WLAN, and up to a few kilometers in the case of a WIMAX. These ranges cannot be easily increased, since the level of reliable transmit power of a network of this type is limited by law in many countries. Since, in addition, these networks are not designed to transmit data between source nodes and target nodes via intermediate nodes, communication between two nodes cannot be carried out when they are further apart than the range of radio contact, even when further nodes of the network are located between these two nodes and the distance between two adjacent nodes does not exceed this range.